Minnesota's Corn Crop Might Fall Short of Last Year's

Wet weather, late planting and an armyworm infestation are just a few of the problems that have plagued the North Star State.

Minnesota’s corn crop appears to have taken the brunt of this year’s abnormally cool, wet weather. Last year, the state produced the largest corn crop in state history, at 1.37 billion bushels on an average yield of 165 bushels per acre. Whether Minnesota producers can best that production this year is uncertain.

"There’s a lot of variability in the corn crop across Minnesota," says Dan Martens, University of Minnesota extension educator for Benton County in central Minnesota. Persistent and consistent rainfall this spring led to late planting, replanting, and soil compaction, he says.

"Corn planting in Minnesota occurred from the first week of May through July 8," notes Martens. While cash-crop producers finished planting in time to meet insurance requirements, beef and dairy farms continued to plant into July, hoping to get silage.

According to USDA’s latest Crop Progress report, only 60 percent of Minnesota’s corn was silking as of July 28, compared with 98 percent last year at this time and a five-year average of 71 percent. Condition ratings, however, were positive, with only 8 percent of the state’s corn crop rated poor or very poor.

"In Benton County, some corn is barely a foot tall," Martens adds. "An early frost could be a huge issue this year." For corn planted between June 15 and July 5, even a frost that occurs near the average first-frost date could cause widespread damage to the crop, he adds.

March of the Armyworms

Adding to the state’s problems, an armyworm infestation moved across a wide arc of cropland, stretching from southeastern South Dakota to southeastern Minnesota in July. The worms caused scattered but widespread damage, reducing some cornfields to stubble. Armyworms, which are uncommon in Minnesota, survive best in cool, wet springs like the one the state had this year.

"It’s probably been 10 years for more since we’ve seen an outbreak like this year’s," says Bruce Potter, a University of Minnesota extension entomologist at the Southwest Research and Outreach Center in Lamberton. "Fields that were heavily infested were totally defoliated." That said, the number of severely infested fields was relatively low.

"The armyworms are the least of the problem," says Potter. Late planting, washed out fields, and now excessive dryness in southwestern Minnesota are much larger issues.

Despite the adversity, the Minnesota corn crop could produce an average yield close to last year’s or even higher, says Jeff Coulter, agronomist with the University of Minnesota, Saint Paul.

"It has been so cool that the crop is using very little water," says Coulter. But some areas of the state, including the southwestern portion, need timely rains within the next seven to 10 days if they are to achieve their potential yields, he adds.